Mercury (Hg) has been recognized as having serious impacts on human health due to its toxicity and bioaccumulation via the food chain. Elevated exposure to Hg can affect the liver, kidneys, and cardiovascular, gastro-intestinal, and neurological systems of the human body. Inorganic Hg (Hg2+) can cause chronic kidney disease (CKD) and kidney failure. Methylmercury (CH3Hg+), an organic form of Hg, is highly toxic to living systems. CH3Hg+ causes nervous system damage leading to problems with coordination, numbness, and visual impairment. Death from CH3Hg+ poisoning usually occurs 2-4 days after the first symptoms occur. Therefore, detecting CH3Hg+ and Hg2+ ions is highly important to human health. Currently, there is no simple, point of care (POC) system for detecting these toxins. To meet this need, InnoSense LLC (ISL) aims to develop a carbon nanotube-based MerSense assay for cost-effective, POC detection of CH3Hg+ and Hg2+ ions with high sensitivity and selectivity. The purpose of the Phase I project is to establish that a MerSense sensor array can accurately detect CH3Hg+ and Hg2+ ions in artificial urine samples. In Phase I, ISL will fabricate and test the MerSense sensor array for detecting trace levels of CH3Hg+ and Hg2+ (d2 ppb) in artificial urine. ISL will also evaluate MerSense performance and demonstrate the sensitivity, selectivity, accuracy, reliability, reproducibility, and real-time sensing capability. Successful development of ISL's MerSense and demonstration of its enhanced performance for Hg detection will have widespread socioeconomic benefits: (1) a simple and cost-effective POC test for improved patient care in clinics, hospitals, private-practice facilities and laboratories, (2) a companion diagnostic tool for pharma and biotech drug discovery and clinical trial research, (3) a new research tool for the scientific community, (4) cost-effective analysis of tailing ponds and run-off in the mining industry for toxic Hg contamination, (5) testing and monitoring drinking water quality by State and Federal agencies, and humanitarian organizations, and (6) trace level detection of Hg at the point of migration to food (air, water and soil) as well as in metal processing, chemical manufacturing and electronics industries.